L2TP AND L2TP/IPSEC PROTOCOL

L2TP stands for Layer 2 Tunnel Protocol, which, by itself does not provide any privacy or encryption to traffic passing through it.

Due to that fact, it is usually implemented together with IPSec suite of protocols to encrypt data before transmission, providing users with privacy and security. All modern VPN compatible devices and operating systems have L2TP/IPsec built in.

The setup is as quick and easy as PPTP, but there can be problems, as the protocol makes use of UDP port 500 which is easy to block by NAT firewalls.

OPENVPN PROTOCOL

OpenVPN is one of the most popular VPN protocols, even though it is one of the more recent protocols. As an open source protocol, it is quite popular, and has a big community of developers and users.

The protocol is highly configurable and can runs on both TCP and UDP. The default OpenVPN port is 1194, but it can be configured to run on any port, which makes it very hard to block. For example, running it on port 443, only DPI (deep packet inspection) firewalls can detect it and block it. And even that can fail if OpenVPN runs behind obfuscation services like stunnel or obfsproxy.

PPTP PROTOCOL

PPTP stands for Point-to-Point Protocol.

Almost every VPN capable device and platform has PPTP available. Since setting it up is relatively easy, it remains the primary choice for both VPN providers and businesses. Also, its implementation requires low computation overhead, making it one of the fastest VPN protocols available.

Even though its very popular, it is obsolete since it’s very insecure, and should not be used.